Pump head increased... How?? 1

[brattong]

Currently due to the increase of pressure drop through the pipes, my pump can no longer support the pump head. The pump is already purchased; may I know what should I do? I was thinking to change the motor to a larger HP one, then I can at least support about 15ft of head. But do you know how much approximately will it cost to change a 7.5hp to a 10hp motor in a end suction centrifugal pump?

 

[gregcase]

I have briefly looked at the responses thus far, so apologize if I am repeating something previously stated. Buying a new motor for a centrifugal pump will probably not incraewse the discharge head 15 ft. Your motor unless it is severly undersized should be run not too far from the nominal operating speed. Check the amps to make sure your under the full load amps (FLA) at you operating point.

Under filing will get you about a 3% head increase if it hasn't already been done at the factory.

The only true way to increase your discharge head is to increade the pump speed or increase the impeller diameter. Buy purchasing a VFD you can greatly increase the control of your flow and head output often while reducing your energy consumption (costs).

When purchasing a new pump it is always a wise idea to purchase a pump with an impeller that is 80% of the full diameter impeller. This gives you room to grow or overcome sizing mistakes made during selection.

You may wish to make an inspection or your current impeller to make sure it is not eroded or damaged.

Greg Case
MechTronix Engineering
Turbomachinery Consultants

 

[KALIYAPERUMAL]

Hey
To increase the head of the pump you have increase the diameter of impeller not the motor.

Usually to increase the discharge reduce the diameter and to increase the head increase the diameter of the impeller. Keep in mind this is the thumb rule